The present invention relates to the peroxy vapor treatment arts, more particularly to hydrogen peroxide vapor sterilization and disinfection. The invention finds particular application in conjunction with hydrogen peroxide vapor sterilization systems in which peroxide vapor is entrained in dry air which has been dried with a desiccant and will be described with particular reference thereto. It is to be appreciated that the present invention may be used with other peroxy vapors in conjunction with disinfection, sanitation, and other treatment processes.
Heretofore, a solution of hydrogen peroxide and water have been vaporized and entrained in dry air. The vapor and air are pumped into a sterilization or other treatment chamber. The hydrogen peroxide reacts with microbial and other decontaminants in an oxidizing reaction which deactivates them and converts the vapor molecule from peroxide to water. To maintain a preselected concentration of hydrogen peroxide in the chamber, air and vapor from the chamber are recirculated to the vaporizer. Hydrogen peroxide vapor in the withdrawn air is decomposed catalytically or by heat to water vapor. The water vapor is then removed from the air, leaving dry air to be recirculated to the vaporizer.
One technique for drying the air was by condensation. However, condensation requires relatively expensive compressors and refrigeration units. Moreover, such condensation units typically fail to dry the air to a consistent level of humidity.
Consistent and lower level of humidity have been achieved by passing the air and water vapor through a desiccant. Although desiccants dry the air consistently to a low humidity, it typically takes longer to regenerate a desiccant than to saturate it. One way to meet these demands was through the use of a desiccant wheel. The air and water vapor were passed through a first portion or section of a desiccant wheel until that section became substantially saturated. The wheel was then indexed, bringing a new desiccant portion or section into the air and water vapor flow path. The saturated portion of the desiccant was subject to a regeneration process over the next several indexed positions of the wheel. Such onboard systems for regenerating desiccant were not only expensive and mechanically complex, but also added significant weight and bulk to portable hydrogen peroxide generation systems.
The present invention provides a new and improved desiccant drying system which overcomes the above-referenced problems.